The Emerging Utility of αβ-Unsaturated Acylammonium Salts for Asymmetric Organocatalysis

摘要

Although acylammonium salts are well-studied, chiral α,β--unsaturated acylammonium salts have received much less attention. While these intermediates are convenient synthons readily available from several commodity unsaturated acids and acid chlorides and possess three reactive sites, their application in organic synthesis has been limited likely due to a lack of appropriate chiral Lewis bases for their generation. In recent years, the utility of chiral, unsaturated acylammonium salts has expanded considerably demonstrating the unique reactivity of this intermediate leading to the development of a diverse array of catalytic, asymmetric transformations including organocascade processes. This Minireview highlights the recent and growing interest in these intermediates which might spark further research into their untapped potential for asymmetric organocascade catalysis. A cursory comparison is made to related unsaturated iminium and acylazolium intermediates.